CN217019011U

CN217019011U - Laser processing system and complementary conical lens group

Info

Publication number: CN217019011U
Application number: CN202123327977.9U
Authority: CN
Inventors: 朱晓鹏; 陈武辉; 吴海涛; 安娜
Original assignee: Tianjin Han Nationality Tiancheng Photoelectric Technology Co ltd
Current assignee: Tianjin Han Nationality Tiancheng Photoelectric Technology Co ltd
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2022-07-22
Anticipated expiration: 2031-12-27

Abstract

The application provides a laser processing system and a complementary conical lens group. Wherein, the laser processing system includes: a laser generating device; a collimating lens with a focus collinear with the light source of the laser generating device; the complementary conical lens group is arranged in the laser propagation direction, is adjacent to the collimating lens and is coaxially distributed; the focusing mirror is arranged in the laser propagation direction, is coaxially distributed with the collimating mirror and is adjacent to the other side of the complementary conical mirror group opposite to the adjacent side of the collimating mirror; wherein, complementary conical lens group includes: a negative conical mirror; a positive conical mirror paired with the negative conical mirror and coaxially rotatable with respect to the negative conical mirror; the projections of the negative conical mirror and the positive conical mirror in the direction of the collimated light beam are in a fan shape. Therefore, the propagation direction of the laser beam can be changed by adjusting the included angle between the negative conical mirror and the positive conical mirror, so that the adjustment of the facula form of the working surface is realized, and the energy distribution of the central area of the output laser is effectively improved.

Description

Laser processing system and complementary conical lens group

Technical Field

The application relates to the technical field of laser processing, in particular to a laser processing system and a complementary conical lens group.

Background

Laser welding is one of the important applications of laser machining technology. When laser welding is carried out, when laser is focused on one point, the energy density of a focusing area is large, a heat affected zone is small, and the laser welding device has the characteristics of small pollution, low material consumption, deep penetration, strong adaptability and the like in the processing process. Laser welding is also used more and more widely.

In the process of realizing the prior art, the inventor finds that:

because the energy of the directly output laser central area is too concentrated, when the laser central area is applied to thin plate welding, adverse phenomena such as splashing, perforation and the like are easy to occur, and the welding effect is poor. Moreover, when the gap between the workpiece plates is large, the problems of incomplete welding seams, unstable welding process and the like are easily caused.

Therefore, it is desirable to provide a laser processing system capable of adjusting the energy of the output laser to adjust the laser output energy according to the actual situation of the workpiece, thereby effectively solving the problems of welding spatter and perforation.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a laser processing system capable of adjusting energy distribution of output laser, which is used for solving the technical problem of energy concentration in the central area of the output laser.

Specifically, a laser beam machining system, characterized by includes:

a laser generating device generating a light source in an excited state;

the focus of the collimating mirror is collinear with the light source of the laser generating device;

the complementary conical lens group is arranged in the laser propagation direction, is adjacent to the collimating lens and is coaxially distributed;

the focusing mirror is arranged in the laser propagation direction, is coaxially distributed with the collimating mirror and is adjacent to the other side, opposite to the adjacent side of the complementary conical mirror group and the collimating mirror;

wherein the complementary conical lens group comprises:

a negative conical mirror;

a positive conical mirror paired with the negative conical mirror and coaxially rotatable with respect to the negative conical mirror;

the negative cone mirror includes:

a first core region;

a negatively tapered mesa region adjoining the first core region;

the positive cone mirror includes:

the second core area corresponds to the first core area and is used for realizing a central light spot;

and the positive conical platform area is adjacent to the second core area and corresponds to the negative conical platform area.

Further, the negative cone mirror further comprises:

an edge region adjacent to the negatively tapered mesa region.

Furthermore, the taper magnitude of the negative taper region is equal to that of the positive taper region.

Further, the negative cone mirror includes:

two sectors with central symmetry;

the radian of each sector is a preset angle.

Further, the negative cone mirror includes:

two separate sub-mirrors;

each sub-mirror is provided with a sector with the radian being a preset angle;

the two sub-mirrors are distributed in central symmetry.

Further, the negative cone mirror is composed of a preset number of discrete sub-mirrors;

each sub-mirror has a sector with a predetermined angle of arc.

The embodiment of the application also provides a complementary conical lens group.

Specifically, a complementary conical lens group is used for a laser processing system, and is characterized by comprising:

a negative cone mirror;

wherein the negative cone mirror comprises:

a first core region;

a negatively tapered mesa region adjoining the first core region;

the positive cone mirror includes:

Further, the negative cone mirror further comprises:

an edge region adjacent to the negatively tapered mesa region.

Further, the negative cone mirror includes:

two sectors with central symmetry;

the radian of each sector is a preset angle.

The technical scheme provided by the embodiment of the application has at least the following beneficial effects:

the included angle between the negative conical mirror and the positive conical mirror is adjusted by rotating the positive conical mirror or the negative conical mirror, so that the propagation direction of the laser beam can be changed, the facula form of the working surface is adjusted, and the energy distribution of the central area of the output laser is effectively improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic structural diagram of a laser processing system according to an embodiment of the present disclosure.

Fig. 2 is a schematic diagram of laser beam propagation according to an embodiment of the present disclosure.

Fig. 3 is a schematic structural diagram of a negative cone mirror provided in an embodiment of the present application.

FIG. 4 is a side view of a negative cone mirror provided in an embodiment of the present application.

Fig. 5 is a schematic structural diagram of a forward conical mirror according to an embodiment of the present application.

FIG. 6 is a side view of a positive axicon provided by an embodiment of the present application.

Fig. 7 is a projection view of a positive/negative cone mirror provided in an embodiment of the present application in a direction parallel to a propagation direction of a laser beam.

Fig. 8 is a projection view of a complementary conical lens group provided in the embodiment of the present application in the propagation direction of parallel laser beams.

Fig. 9 is a distribution diagram of spots of an output laser beam according to an embodiment of the present disclosure.

Fig. 10 is a projection view of another complementary set of conical mirrors provided in the embodiments of the present application in the direction of propagation of parallel laser beams.

Fig. 11 is a distribution diagram of spots of another output laser beam provided in the embodiments of the present application.

Fig. 12 is a schematic view of another laser beam propagation provided in an embodiment of the present application.

Fig. 13 is a projection view of a positive/negative cone mirror provided in an embodiment of the present application in a direction parallel to a propagation direction of a laser beam.

Fig. 14 is a projection view of a complementary set of conical mirrors provided in an embodiment of the present application in a direction parallel to a propagation direction of a laser beam.

Fig. 15 is a schematic structural diagram of a lens of a laser processing system according to an embodiment of the present disclosure.

Fig. 16 is a schematic structural diagram of a rotation mechanism according to an embodiment of the present application.

100 laser processing system

11 laser generator

12 collimating mirror

13 complementary conical lens group

131 negative conical mirror

1311 first core area

1312 negative tapered plateau

1313 edge zone

132 regular cone mirror

1321 second core region

1322 right conical platform area

14 focusing mirror

15 lens barrel

151 collimating lens barrel

152 focus lens barrel

1521 rotating mechanism

15211 internal swivel ring

15212 outer swivel ring

15213 connecting piece

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be clearly and completely described below with reference to specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It is understood that laser processing systems are widely used, and have been oriented in the fields of optoelectronics, material processing, military, and the like. The laser processing system that this application provided is mainly applied to the material processing field, for example, fields such as material cutting, circuit board processing, material welding. Due to the high stability and high efficiency of the laser, it can easily perform precise processing on industrial materials. When the laser is focused on one point, the energy density of a focusing area is large, a heat affected zone is small, and the laser has the characteristics of small pollution, low material consumption, deep penetration, strong adaptability and the like in the processing process. However, since the directly outputted laser energy is concentrated, when the laser energy is applied to thin plate welding, undesirable phenomena such as splashing and perforation are likely to occur, and when the gap between the workpiece plates is large, problems such as unstable welding process and incomplete welding seam are likely to occur. Although the energy distribution of the edge of the annular light spot is uniform, the problems of welding spatter, perforation and the like can be effectively solved. However, the semiconductor laser has a large divergence angle, and if a structure with a long optical path is used, the aperture of the device is large, and the device is inconvenient to apply. The existing lens combination realizes the structure of annular light spots, such as the structure of a double-cone lens or the structure of a refraction and reflection light path, and the light path is longer and is not suitable for a laser processing system.

It should be noted that in laser welding, the energy distribution is related to the area ratio of the transmitted beam. Therefore, the laser energy distributed by the annular light spot area is different from that distributed by the point light spot area. The energy distribution adjustment of the annular light spot region and the point light spot region can be realized by adjusting the areas of the point light spot region and the annular light spot region. The area of the annular light spot area is adjusted by converting the annular light spot into a plurality of arc-shaped light spots. The area of the arc-shaped light spot is changed by adjusting the sum of the corresponding central angle angles of the arc-shaped light spot. The area of the arc-shaped light spot is increased, and the energy of the arc-shaped light spot area is increased. Correspondingly, the energy of the central spot area becomes lower. The areas of the point light spot region and the annular light spot region can be adjusted through corresponding lens combinations. In other words, in the collimating focusing light path, a lens combination capable of adjusting the area ratio of a point light spot area to an annular light spot area is added to change the propagation direction of all or part of the laser beam, so that the purpose of changing the light spot form is achieved. The lens combination capable of adjusting the area ratio of the point light spot area to the annular light spot area is added on the basis of the original light path of the laser processing system, so that the processing requirements under different application scenes can be met. And the structure is compact, and the influence on the optical path length is small.

Referring to fig. 1-7, a laser processing system 100 is disclosed having a complementary set of conical mirrors 13 capable of adjusting the area ratio of a spot area to an annular spot area. Arc-shaped light spots with different sizes can be obtained by rotating the negative conical mirror 131 or the positive conical mirror 132 in the complementary conical mirror group 13 and adjusting the included angle between the negative conical mirror 131 and the positive conical mirror 132. When the overlapped parts of the two lenses are more, the energy of the central light spot is high, and the energy of the arc-shaped light spot is low; when the overlapping part is less, the energy of the central light spot is low, and the energy of the arc-shaped light spot is high. Specifically, a laser processing system 100 includes:

a laser generator 11 for generating a light source in an excited state;

a collimator 12, a focus of the collimator 12 and a light source of the laser generator 11 being collinear;

a complementary conical lens group 13 which is arranged in the laser propagation direction, is adjacent to the collimating lens 12 and is coaxially distributed;

the focusing mirror 14 is arranged in the laser propagation direction, is coaxially distributed with the collimating mirror 12, and is adjacent to the other side of the complementary conical mirror group 13 opposite to the adjacent side of the collimating mirror 12;

wherein the set of complementary conical lenses 13 comprises: a negative cone mirror 131; a positive conical mirror 132 paired with the negative conical mirror 131 and coaxially rotatable with respect to the negative conical mirror 131;

the negative cone mirror 131 includes: a first core region 1311; a negative tapered mesa region 1312 adjacent to the first core region 1311;

the positive cone mirror 132 includes: a second core region 1321 corresponding to the first core region 1311 and configured to implement a central light spot; a positive tapered mesa region 1322 adjacent to the second core region 1321 and corresponding to the negative tapered mesa region 1312.

It will be appreciated that the laser light is generated without departing from the stimulated emission. In a thermal equilibrium state, the population of the high-energy state is less than that of the low-energy state, and the population of the high-energy state is more than that of the low-energy state required for the stimulated radiation, so that the necessary condition for generating the laser is that the working substance is in a population inversion distribution state. The laser generator 11 is used here to generate a light source in the excited state, i.e. to achieve a population inversion, and to generate a laser beam. The laser light source generated by the laser generator 11 can generate different types of laser beams according to the activating substances. It is understood that the specific type of activating substance selected for the laser generating device 11 is not a limitation to the scope of the present application.

The collimator 12 is mainly used to convert the laser beam generated by the laser generator 11 into a parallel laser beam. It will be appreciated that there is a certain divergence angle of the laser beam generated by the light source at the laser generating device 11. The incident light of the collimator 12 is the laser beam with a certain divergence angle. The laser beam is refracted by the collimating mirror 12 to be a parallel beam. In practical applications, the collimator 12 is typically a convex lens. The light is transmitted by the convex lens, and the transmission direction of the light passing through the optical center is unchanged; the light parallel to the main optical axis is refracted and passes through the focus of the light; the light rays passing through the focal point are refracted and then parallel to the main optical axis. From this, it can be seen that if the laser beam propagating through the collimator 12 is a parallel beam, the focal point of the collimator 12 and the light source of the laser generator 11 need to be collinear, and the light source of the laser generator 11 and the focal point of the collimator 12 need to be coincident with each other. The specific material and shape of the collimator 12 can be chosen flexibly according to the actual situation.

And a complementary conical lens group 13 which is arranged in the laser propagation direction, is adjacent to the collimating lens 12 and is coaxially distributed. The complementary conical lens group 13 is mainly used for adjusting the area ratio of the point light spot area to the annular light spot area. The set of complementary conical lenses 13 comprises: a negative conical mirror 131, and a positive conical mirror 132 paired with the negative conical mirror 131 and coaxially rotatable with respect to the negative conical mirror 131.

In detail, referring to fig. 3 to 7, the negative conical mirror 131 includes: a first core region 1311; a negatively tapered mesa region 1312 adjacent to the first core region 1311. The first core region 1311 may be understood here as a region where the propagation direction of the parallel laser beam is not changed. That is, the parallel laser beam propagates through the first core region 1311 of the negative cone mirror 131 without changing the propagation direction. In practical applications, the first core region 1311 may be a region of the negative cone mirror 131 where the light beam incident surface is parallel to the light beam exit surface, or a virtual hollow region without any solid in the propagation direction of the laser beam. Here, the negative cone-shaped mesa 1312 may be understood as a region where a cone surface is located higher than the light beam exit surface of the first core region 1311 in the light beam propagation direction. The angle between the tapered surface and the first core region 1311 may be designed according to practical circumstances. Here, the first core region 1311 may be understood as being in a spatially connected relationship with the negative tapered mesa region 1312.

It should be noted that the tapered surface of the negative taper plateau 1312 is not a continuous conical surface. That is, the arcs at the edges of the negatively tapered mesa 1312 correspond to a central angle other than 360. That is, referring to FIG. 7, the projection of the negatively tapered mesa region 1312 onto the parallel laser beam propagation direction is not circular, but is fan-shaped.

Further, in a preferred embodiment provided herein, the negative conical mirror 131 further includes: an edge region 1313 adjacent to the negative tapered mesa region 1312. An edge region 1313 is provided here to facilitate the processing and protection of the negative cone 131. It can be understood as the area of the negative cone mirror 131 that is not coplanar with the negative cone mesa 1312. Since the emergent surface of the edge region 1313 is not coplanar with the negative tapered mesa region 1312, that is, the included angle between the extending surface of the edge region 1313 and the emergent surface of the first core region 1311 is different from the included angle between the emergent surface of the negative tapered mesa region 1312 and the emergent surface of the first core region 1311, the propagation direction of the parallel laser beam on the emergent surface of the edge region 1313 is different from the propagation direction of the laser beam emitted from the negative tapered mesa region 1312. If the included angle of the extended surface of the edge region 1313 with respect to the exit surface of the first core region 1311 is smaller than the included angle of the negative tapered mesa region 1312 with respect to the exit surface of the first core region 1311, that is, the inclination of the extended surface of the edge region 1313 with respect to the exit surface of the first core region 1311 increases, the propagation of the laser beam emitted through the edge region 1313 is more diffused. If the included angle of the extension surface of the edge region 1313 with respect to the exit surface of the first core region 1311 is greater than the included angle of the exit surface of the negative tapered mesa region 1312 with respect to the exit surface of the first core region 1311, that is, the inclination of the extension surface of the edge region 1313 with respect to the exit surface of the first core region 1311 is reduced, the propagation of the laser beam exiting through the edge region 1313 is more convergent. If the edge region 1313 is parallel to the first core region 1311, the propagation direction of the light beam is unchanged compared to the incident light.

In a preferred embodiment provided herein, the plane in which the edge region 1313 lies is perpendicular to the axis of the negative cone mirror 131, i.e. the edge region 1313 is parallel to the first core region 1311. The light beam emitted through the edge region 1313 has a constant propagation direction. Therefore, the negative conical mirror 131 is convenient to mount in the lens, the total edge breakage phenomenon in the machining process is prevented, and the machining yield of the negative conical mirror 131 is improved.

The positive cone mirror 132 includes: a second core region 1321 corresponding to the first core region 1311 and configured to implement a center light spot; a positive tapered land 1322 adjacent to the second core area 1321 and corresponding to the negative tapered land 1312. Second core region 1321 is understood here to be a region which is adjacent to first core region 1311 and which is of comparable size and does not change the direction of propagation of the parallel laser beam. That is, the parallel laser beam propagating through the first core region 1311 propagates through the second core region 1321 of the positive tapered mirror 132 without changing the propagation direction. In one embodiment provided herein, the second core region 1321 overlaps the first core region 1311 in a projection parallel to the direction of propagation of the laser beam. In practical applications, the second core region 1321 may be an area adjacent to the first core region 1311 and having a size corresponding to that of the beam incident surface and the beam emergent surface, or a virtual hollow-out area without any solid in the direction parallel to the propagation direction of the laser beam. The size of the gap between the second core region 1321 and the first core region 1311 has a small influence on the entire optical path length, which can be ignored. Generally, a gap of less than 1mm is reserved to prevent the negative cone mirror 131 and the positive cone mirror 132 from scratching. Here, the positive tapered mesa regions 1322 can be understood as regions where the tapered surface complementary to the negative tapered mesa regions 1312 is located in the direction of beam propagation. It should be noted that the complementary refers to the spatial relationship that the positive tapered mesa region 1322 and the negative tapered mesa region 1312 exhibit when they overlap. Here, the abutment may be understood as the spatial connection of the second core region 1321 and the forward tapered platform region 1322. The angle between the tapered surface of the positive tapered mesa 1322 and the second core 1321 may be designed according to the angle between the negative tapered mesa 1312 and the first core 1311. The tapered surface of the forward tapered mesa region 1322 is not a continuous conical surface. That is, the arcs of the edges of the forward tapered lands 1322 correspond to central angles other than 360 °. That is, referring to fig. 7, the projection of the forward tapered land 1322 in the direction parallel to the propagation direction of the laser beam is not circular, but is fan-shaped. The tapered surface of the positive tapered land 1322 can be designed according to the tapered surface of the negative tapered land 1312, so that the positive tapered mirror 132 can rotate coaxially with respect to the negative tapered mirror 131.

In one embodiment provided by the present application, a side (incidence surface) of the negative conical mirror 131 close to the collimator mirror 12 may be a plane perpendicular to a propagation direction of the light beam; the side of the positively tapered mirror 132 remote from the collimator mirror 12 (exit face) may be a plane perpendicular to the direction of propagation of the light beam. And, a space for facilitating the rotation of the lens is provided between the negative conical mirror 131 and the positive conical mirror 132.

Specifically, a side (incident surface) of the negative conical mirror 131 close to the collimator mirror 12 may be a plane perpendicular to a beam propagation direction, that is, a plane of incidence of the parallel laser beam propagated through the collimator mirror 12 is perpendicularly incident on the negative conical mirror 131. In other words, the projections of the first core region 1311, the negative cone mesa region 1312 and the edge region 1313 in the direction parallel to the propagation direction of the laser beam collectively constitute the incident surface of the negative cone mirror 131. At this time, since the exit surface of the laser beam propagating through the first core region 1311 is parallel to the incident surface, the propagation direction of the laser beam does not change. The laser beam propagating through the negative tapered mesa 1312 diverges because there is a certain angle between the exit surface and the entrance surface.

The side (exit surface) of the positive conical mirror 132 remote from the collimator mirror 12 may be a plane perpendicular to the beam propagation direction, i.e., the exit surface of the positive conical mirror 132 is parallel to the entrance surface of the negative conical mirror 131 in the direction parallel to the propagation direction of the laser beam. In other words, the projections of the second core region 1321 and the normal cone 1322 in the direction parallel to the propagation direction of the laser beam jointly constitute the incident surface of the normal cone mirror 132. The incident surfaces of the positive cone mirror 132 are a second core region 1321 corresponding to the first core region 1311, and a positive cone mesa region 1322 corresponding to the negative cone mesa region 1312. Since the second core region 1321 corresponds to the first core region 1311, the propagation direction of the parallel laser beam emitted from the first core region 1311 is unchanged by the propagation of the second core region 1321. The laser beam incident through the forward tapered mesa region 1322 can be condensed.

It is noted that the negative cone-shaped land 1312 and the projection of the cone-shaped land in the direction parallel to the propagation direction of the laser beam are not circular, but fan-shaped. Moreover, since the negative conical mirror 131 and the positive conical mirror 132 can rotate, the included angle between the negative conical mirror 131 and the positive conical mirror 132 can be adjusted by rotating the same. In order to reduce the influence of the rotating gap between the positive conical mirror 132 and the negative conical mirror 131 on the laser beam propagation and ensure that the positive conical mirror 132 and the negative conical mirror 131 can rotate stably, in a preferred embodiment provided by the present application, the taper of the negative conical mesa 1312 and the taper of the positive conical mesa 1322 are equal in magnitude. Moreover, in order to ensure that the positive conical mirror 132 and the negative conical mirror 131 have the same effect on the propagation of the laser beam, in a preferred embodiment provided by the present application, the negative conical mirror 131 and the positive conical mirror 132 are made of materials having the same refractive index for light. The specific refractive index of the negative conical mirror 131 and the positive conical mirror 132 can be selected according to practical situations.

It will be appreciated that the relative positions of the negative cone mirror 131 and the positive cone mirror 132 determine the direction of propagation of the laser beam exiting through the complementary set of cone mirrors 13. When the negative conical mirror 131 or the positive conical mirror 132 is rotated to adjust the included angle therebetween, the relative positions of the first core region 1311 and the second core region 1321 are not changed.

When the negative conical mirror 131 coincides with the positive conical mirror 132, the rotation angle therebetween is 0 °. At this time, the projections of the negative tapered land 1312 and the positive tapered land 1322 in the parallel laser beam propagation direction overlap. Since the incident surface of the negative conical mirror 131 is a plane perpendicular to the propagation direction of the light beam, and the exit surface of the positive conical mirror 132 is a plane perpendicular to the propagation direction of the light beam, the incident surface and the exit surface of the complementary conical mirror group 13 are parallel. And the distance between the two is small, which is equivalent to inserting a parallel flat plate in the light path. When the incident light is a parallel beam, the propagation direction is not changed. At this time, part of the parallel laser beams emitted from the collimator lens 12 is propagated by the complementary conical lens group 13. Since the projections of the negative tapered mesa 1312 and the tapered mesa in the propagation direction of the parallel laser beam are fan-shaped, a part of the parallel laser beam emitted from the collimating mirror 12 is still the laser beam that has not propagated through the complementary tapered mirror group 13. This portion of the laser beam does not change its propagation direction and is directly incident on the focusing mirror 14. In summary, when the negative conical mirror 131 coincides with the positive conical mirror 132, the propagation direction of the parallel laser beam emitted from the collimating mirror 12 does not change.

The position where the negative conical mirror 131 and the positive conical mirror 132 are overlapped is taken as a starting point, any lens in the complementary conical mirror group 13 is rotated in any direction around the axis, and the included angle between the negative conical mirror 131 and the positive conical mirror 132 is changed. During the rotation, if there is still a partial overlap region between the negative conical mirror 131 and the positive conical mirror 132, the propagation direction of the parallel laser beam propagating through the overlap region is not changed. At this time, the negative cone mirror 131 and the positive cone mirror 132 have respective regions that are partially not overlapped, and the negative cone region 1312 and the projection of the cone region in the direction parallel to the propagation direction of the laser beam partially overlap. That is, the incident surface of the complementary set of conical mirrors 13 includes part of the positively conical mesa 1322 of the positively conical mirror 132 in addition to the incident surface of the negatively conical mirror 131; the exit surface of the set of complementary conical mirrors 13 comprises in addition to the exit surface of the positive conical mirror 132 also a part of the negative conical plateau 1312 of the negative conical mirror 131. At this time, a part of the parallel laser beam emitted from the collimator lens 12 directly enters the normal tapered mesa 1322 which is an overlapping part, and the beam is converged. There is also a portion of the parallel laser beam exiting through the collimator lens 12 that exits directly from the negative tapered mesa 1312, which is the overlapping portion, and the beam diverges. It should be noted that there may still be a part of the parallel laser beam exiting through the collimating mirror 12 that is not propagated by the complementary set of conical mirrors 13. This portion of the laser beam, which does not change the propagation direction, is directly incident on the focusing mirror 14. In summary, when the negative conical mirror 131 and the positive conical mirror 132 rotate to have a partial overlapping region, the parallel laser beams emitted from the collimating mirror 12 are propagated by the complementary conical mirror group 13, and then laser beams in converging, diverging and parallel states compared with the original parallel laser beams are obtained respectively.

During rotation, if there is no overlapping area between the negative cone mirror 131 and the positive cone mirror 132, there is no overlapping area in the projections of the negative cone mesa region 1312 and the positive cone mesa region 1322 in the direction parallel to the propagation direction of the laser beam. At this time, the incident surface of the complementary set of conical mirrors 13 includes a positive conical land 1322 of the positive conical mirror 132 in addition to the incident surface of the negative conical mirror 131; the exit surface of the set of complementary conical mirrors 13 comprises, in addition to the exit surface of the positive conical mirror 132, a negative conical plateau 1312 of the negative conical mirror 131. At this time, a part of the parallel laser beam emitted from the collimator lens 12 directly enters the forward tapered mesa 1322, and the beam is converged. The parallel laser beam emitted by the collimating mirror 12 still has a part directly emitted by the negative cone-shaped mesa 1312, and the beam is divergent. It should be noted that there may still be a part of the parallel laser beam exiting through the collimating mirror 12 that is not propagated by the complementary set of conical mirrors 13. This portion of the laser beam, which does not change the propagation direction, is directly incident on the focusing mirror 14. Since the relative positions of the first core region 1311 and the second core region 1321 are not changed when the negative conical mirror 131 or the positive conical mirror 132 is rotated to adjust the included angle therebetween, the propagation direction of the laser beam propagating through the first core region 1311 and the second core region 1321 is not changed, and the laser beam is still a parallel beam. In summary, when the negative conical mirror 131 and the positive conical mirror 132 are rotated and there is no overlapping area, the parallel laser beams emitted from the collimating mirror 12 are propagated by the complementary conical mirror group 13, and then the converging, diverging and parallel laser beams compared with the original parallel beams are obtained respectively.

The parallel laser beams emitted by the collimating lens 12 are transmitted by the complementary conical lens group 13 in any state and enter the focusing lens 14. It should be noted that the laser beam incident on the focusing mirror 14 may include parallel laser beams that do not propagate through the complementary conical mirror group 13, in addition to the laser beam emitted by the complementary conical mirror group 13. The focusing lens 14 is disposed in the laser propagation direction and coaxially distributed with the collimating lens 12, and is adjacent to the other side of the complementary conical lens group 13 opposite to the adjacent side of the collimating lens 12. That is, the focusing mirror 14 is coaxially disposed with the collimating mirror 12 and the complementary conical mirror group 13, and the incident surface of the focusing mirror 14 is adjacent to the positive conical mirror 132 in the complementary conical mirror group 13. The focusing lens 14 is mainly used for focusing the laser beam emitted by the complementary conical lens group 13. In practical applications, the collimator 12 is typically a convex lens. When the light is transmitted by the convex lens, the light transmission direction through the optical center is unchanged; the light parallel to the main optical axis is refracted and passes through the focus of the light; the light rays passing through the focal point are refracted and then parallel to the main optical axis. If the incident beam of the focusing mirror 14 is a parallel beam, the beam is propagated by the focusing mirror 14, and a light spot with concentrated energy is finally obtained.

In one embodiment provided by the present application, when the negative conical mirror 131 coincides with the positive conical mirror 132, and the light beam emitted through the complementary conical mirror group 13 enters the focusing mirror 14, a light spot with concentrated energy is obtained. The size of the light spot is realized by adjusting the distance between the surface of the workpiece to be processed and the focusing mirror 14. The specific material and shape of the focusing lens 14 can be flexibly selected according to actual conditions.

It is understood that when the negative conical mirror 131 and the positive conical mirror 132 are rotated, the laser beams are converged, diverged and parallel to the parallel beam emitted from the collimating mirror 12, respectively. Wherein, the laser beam which is parallel to the parallel beam emitted from the collimating mirror 12 is transmitted through the focusing mirror 14, and a spot can be obtained on the working surface. That is, when the negative conical mirror 131 is partially overlapped with the positive conical mirror 132, the light beam propagating through the overlapped portion of the complementary conical mirror group 13 propagates through the focusing mirror 14 to form the central spot. Alternatively, the central spot is formed by the part of the parallel laser beam that does not propagate through the complementary set of conical mirrors 13 propagating through the focusing mirror 14. Compared with the laser beam emitted by the collimating mirror 12 and in a divergent state, the laser beam is transmitted through the focusing mirror 14, and two symmetrical arc-shaped light spots can be obtained on the working surface. Compared with the laser beam which is emitted by the collimating mirror 12 and is in a convergent state, the laser beam is transmitted through the focusing mirror 14, the laser beam is firstly converged at a focal point, and when the laser beam is continuously transmitted, the laser beam is divergent. When the working surface is positioned behind the focal point, two symmetrical arc-shaped light spots with the same size as the two symmetrical arc-shaped light spots can be obtained on the working surface. It should be noted that when the rotation angles of the negative conical mirror 131 and the positive conical mirror 132 are different, arc-shaped light spots with different sizes can be obtained. The length of the resulting arc-shaped spot is determined by the design values of the central angles of the negative tapered mesa 1312 and the positive tapered mesa 1322.

Specifically, when the overlapping portion of the negative conical mirror 131 and the positive conical mirror 132 is large, the resulting arc-shaped spot area is small. At the moment, the area of the arc-shaped light spot area is smaller than that of the point light spot area, the energy of the central light spot is high, and the energy of the arc-shaped light spot is low. When the overlapping portion of the negative conical mirror 131 and the positive conical mirror 132 is small, the resulting arc-shaped spot area is large. The change of the area of the arc-shaped light spot is mainly reflected in the change of the arc-shaped length parameter of the arc-shaped light spot, and the width value of the arc-shaped light spot in the radial direction is not changed. At the moment, the area of the arc-shaped light spot area and the area of the point light spot area are larger, the energy of the central light spot is low, and the energy of the arc-shaped light spot is high. In addition, the outer diameter of the arc-shaped light spot is determined by the included angle between the negative cone-shaped platform region 1312 and the first core region 1311 and the included angle between the positive cone-shaped platform region 1322 and the second core region 1321. The larger the angle between the negative tapered mesa 1312 and the first core region 1311, the larger the angle between the positive tapered mesa 1322 and the second core region 1321, and the larger the angle at which the arc-shaped spot is offset. In this case, the outer diameter of the annular spot is larger under the condition that the focal length and the working distance are fixed. The angle between the negative tapered mesa region 1312 and the first core region 1311 and the angle between the positive tapered mesa region 1322 and the second core region 1321 may be designed according to the practical usage and requirements.

Experiments show that the energy distribution between the arc-shaped light spots and the point light spots is related to the area ratio of the transmitted light beams, and the energy and the angle change form a linear relation. For example, when the negative conical mirror 131 partially overlaps the positive conical mirror 132, the light beam propagating through the overlapping portion of the complementary conical mirror group 13 propagates through the focusing mirror 14 to form a central light spot. If the total energy percentage of all the laser beams emitted by the focusing mirror 14 is 100%, the beam passing through the part accounts for 50%, and the edge-to-center energy ratio is theoretically 1: 1. The overlapping area of the projections of the negative conical mirror 131 and the positive conical mirror 132 in the direction of propagation of the parallel laser beam includes: an overlapping area of the first core region 1311 and the second core region 1321; the area of overlap of the projections of the negative tapered mesa 1312 and the positive tapered mesa 1322 in the direction of propagation of the parallel laser beam. Wherein the overlapping area of the projection of the negative tapered mesa region 1312 and the positive tapered mesa region 1322 in the direction parallel to the propagation direction of the laser beam is related to the angle corresponding to the overlapping fan. The area sizes of the first core region 1311 and the second core region 1321 may be designed according to the energy requirement of the central light spot, and may be designed to be circular. Also, the overlapping area of the first core region 1311 and the second core region 1321 does not change with the rotation angle of the negative tapered mirror 131 and the positive tapered mirror 132.

In a preferred embodiment provided by the present application, the sum of central angles corresponding to sectors obtained by projecting the negative frustum 1312 and the positive frustum 1322 in the direction parallel to the propagation direction of the laser beam is 360 °, that is, the sum of central angles corresponding to the arcs at the edges of the negative frustum 1312 and the positive frustum 1322 is 360 °. Thus, when the negative cone mirror 131 and the positive cone mirror 132 are rotated to a certain angle, the negative cone-shaped land 1312 and the positive cone-shaped land 1322 are projected in a circular shape in the direction parallel to the propagation direction of the laser beam. At this time, a complete annular light spot on the surface of the workpiece can be obtained. With the rotation of the negative conical mirror 131 and the positive conical mirror 132, the projection of the negative conical land 1312 and the positive conical land 1322 on the propagation direction of the parallel laser beam changes, and the projections are distributed in a plurality of sectors. At the moment, a plurality of arc-shaped light spots can be obtained on the surface of the workpiece. Therefore, light spots in various different forms can be obtained on the surface of the workpiece, and flexible switching can be performed according to actual processing scenes.

Further, in a preferred embodiment provided by the present application, referring to fig. 8, the negative conical mirror 131 includes: two sectors with central symmetry; the radian of each sector is a preset angle. The two centrosymmetric sectors, i.e. the negative cone mirror 131, here comprise two centrosymmetric sectors projected in the propagation direction of the parallel laser beam. In one embodiment provided by the present application, each sector arc is 90 degrees, i.e. the central angle of the fan-shaped projection of the negative conical mirror 131 in the direction of propagation of the parallel laser beam is 90 °. At this time, correspondingly, the positive conical mirror 132 includes two sectors that are centrosymmetric, and each sector arc is 90 degrees.

When the positive conical mirrors 132 and the negative conical mirrors 131 are all overlapped, the propagation direction of the light beam propagating through the complementary conical mirrors is unchanged. At this time, the projection of the complementary conical mirror group 13 in the propagation direction of the parallel laser beam includes two centrosymmetric sectors, and each sector has an arc of 90 degrees. Under the action of the focusing lens 14, the laser beam emitted by the complementary conical lens group 13 finally forms a spot on the surface of the workpiece.

Referring to fig. 9, when any one of the positive conical mirror 132 or the negative conical mirror 131 is rotated by 90 degrees, and there is no overlapping area between the positive conical mirror 132 and the negative conical mirror 131, the projection of the complementary conical mirror group 13 in the direction parallel to the propagation direction of the laser beam is a circle, which includes four sectors, each of which has an arc of 90 degrees. At this point, the positive tapered mirror 132 is completely separated from the rest of the negative tapered mirror 131, except that the first core region 1311 coincides with the second core region 1321. The incident surface of the complementary set of conical mirrors 13 is the incident surface of the negative conical mirror 131 and the positive conical mesa 1322 of the positive conical mirror 132. The laser beam incident through the incident surface of the negative cone mirror 131 is emitted from the negative cone 1312 and enters the focusing mirror 14. After the propagation of the focusing mirror 14, two symmetrical quarter circular arc-shaped light spots are finally formed on the surface of the workpiece. The laser beam incident through the forward tapered land 1322 of the forward tapered mirror 132 is emitted from the exit surface of the forward tapered mirror 132 and enters the focusing mirror 14. After the propagation of the focusing mirror 14, the light beam is firstly converged at the focal point, and when the propagation is continued, the light beam is diverged. When the working surface is positioned behind the focal point, two symmetrical quarter circular arc-shaped light spots with the same size as the size can be formed on the surface of the workpiece. It is noted that the optical beam incident through the first core region 1311 exits through the second core region 1321 with a constant propagation direction. And finally forming a point light spot on the surface of the workpiece through the propagation of the focusing mirror 14. The four quarter arc-shaped light spots form a complete annular light spot, and the complete annular light spot and the central point light spot form a point annular light spot.

Referring to fig. 10-11, when either the positive conical mirror 132 or the negative conical mirror 131 is rotated by any angle between 0-90 degrees, for example, 60 degrees, the positive conical mirror 132 partially overlaps the negative conical mirror 131. The projection of the complementary conical lens group 13 in the propagation direction of the parallel laser beam is fan-shaped. At this point, the negative tapered mesa regions 1312 and the positive tapered mesa regions 1322 have an overlapping region at an angle of 30 ° except that the first core region 1311 and the second core region 1321 coincide. The parallel laser beams propagate through the overlapping region (including the first core region 1311 and the second core region 1321), and the emergent rays are still parallel beams and are incident on the focusing mirror 14. This portion of the beam eventually forms a spot on the workpiece surface as it propagates through the focusing mirror 14. The parallel laser beams are transmitted through the non-overlapping area in the complementary conical lens group 13, and finally four discontinuous arc-shaped light spots are formed on the surface of the workpiece. The central angle corresponding to each arc-shaped light spot is 60 degrees, which is the same as the rotation angle of the positive/negative conical mirror. Arc-shaped light spots in different distribution states can be obtained by continuously adjusting the rotation angle of any one of the positive conical mirror 132 or the negative conical mirror 131, so that different requirements under different application scenes are met.

It should be noted that, the positive conical mirror 132 and the negative conical mirror 131 are designed as two central symmetric sectors, and the radian of each sector is 90 degrees, so that the switching between a circular light spot and an arc-shaped light spot can be realized by using the least number of lenses, and the optical path length is less affected and the structure is compact.

Further, in a preferred embodiment provided by the present application, the negative conical mirror 131 includes: two separate sub-mirrors; each sub-mirror is provided with a sector with the radian being a preset angle; the two sub mirrors are distributed in a central symmetry way. The separation here can be understood as the difference between the two sub-mirrors in the negative cone mirror 131 at a common connection. In one embodiment provided herein, the predetermined angle is 90 °. At this time, the projections of the two sub-mirrors in the propagation direction of the parallel laser beam are two sectors in a central symmetry and no connection relationship, and the radian of each sector is 90 degrees. Here, two separate sub-mirrors in the negative cone mirror 131 can be fixed to the same barrel to achieve a spatial relationship with their centers symmetrically distributed. The incident planes of the two sub-mirrors are coplanar and are positioned in the same plane perpendicular to the optical axis. Correspondingly, the positive conical mirror 132 comprises two sectors which are centrosymmetric, and the radian of each sector is 90 degrees; the two sub mirrors are distributed in a central symmetry way. Similarly, two separate sub-mirrors in the forward conical mirror 132 can also be fixed to the same lens barrel to achieve a spatial relationship with their centers symmetrically distributed. Moreover, the incident planes of the two separate sub-mirrors in the forward conical mirror 132 are coplanar and are located in the same plane perpendicular to the optical axis. In this case, the first core region 1311 and the second core region 1321 may be understood as a virtual region without any solid matter in the direction parallel to the propagation direction of the laser beam, and are a circular hole, and the center line of the circular hole coincides with the beam axis.

When the positive conical mirror 132 and the negative conical mirror 131 are all overlapped, the propagation direction of the light beam propagating through the complementary conical mirror is unchanged. At this time, the projection of the complementary conical mirror group 13 in the propagation direction of the parallel laser beam is two sectors in a centrosymmetric and connectionless relationship, and the radian of each sector is 90 °. Under the action of the focusing lens 14, the laser beam emitted by the complementary conical lens group 13 finally forms a spot on the surface of the workpiece.

When any one of the positive conical mirror 132 or the negative conical mirror 131 is rotated by 90 degrees and there is no overlapping region between the positive conical mirror 132 and the negative conical mirror 131, the projection of the complementary conical mirror group 13 in the direction parallel to the propagation direction of the laser beam is a circle, and the projection includes four sectors, and the radian of each sector is 90 degrees. At this time, the positive conical mirror 132 is completely separated from the negative conical mirror 131. The incident surface of the complementary set of conical mirrors 13 is the incident surface of the negative conical mirror 131 and the positive conical mesa 1322 of the positive conical mirror 132. The laser beam incident through the incident surface of the negative cone mirror 131 is emitted from the negative cone 1312 and enters the focusing mirror 14. And finally two symmetrical quarter arc-shaped light spots are formed on the surface of the workpiece through the propagation of the focusing mirror 14. The laser beam incident through the forward tapered land 1322 of the forward tapered mirror 132 is emitted from the exit surface of the forward tapered mirror 132 and enters the focusing mirror 14. After the propagation of the focusing mirror 14, the light beam is firstly converged at the focal point, and when the propagation is continued, the light beam is diverged. When the working face is positioned behind the focal point, two symmetrical quarter circular arc-shaped light spots with the same size as the focal point can be formed on the surface of the workpiece. It is noted that the optical beam incident through the first core region 1311 exits through the second core region 1321 with a constant propagation direction. And finally forming a point light spot on the surface of the workpiece through the propagation of the focusing mirror 14. The four quarter arc-shaped light spots form a complete annular light spot, and the complete annular light spot and the central-point light spot form a point annular light spot.

When either the positive conical mirror 132 or the negative conical mirror 131 is rotated by any angle between 0 deg. -90 deg., such as 60 deg., the positive conical mirror 132 partially overlaps the negative conical mirror 131. The projection of the complementary conical lens group 13 in the direction parallel to the propagation direction of the laser beam is fan-shaped. At this point, there is a 30 ° angle overlap region between the negative tapered land 1312 and the positive tapered land 1322. The parallel laser beams propagate through the overlapping region (including the first core region 1311 and the second core region 1321), and the emergent rays are still parallel beams and enter the focusing mirror 14. This portion of the beam, propagating through the focusing mirror 14, eventually forms a spot on the workpiece surface. The parallel laser beams are transmitted through the non-overlapping area in the complementary conical lens group 13, and finally four discontinuous arc-shaped light spots are formed on the surface of the workpiece. The central angle corresponding to each arc-shaped light spot is 60 degrees, which is the same as the rotation angle of the positive/negative conical mirror. Arc-shaped light spots in different distribution states can be obtained by continuously adjusting the rotation angle of any one of the positive conical mirror 132 or the negative conical mirror 131, so that different requirements under different application scenes are met.

It should be noted that, by designing the positive conical mirror 132 and the negative conical mirror 131 as centrosymmetric, separate sub-mirrors, and each sub-mirror has a sector with an arc of 90 degrees, the switching between the circular light spot and the arc light spot can be realized with the minimum number of lenses, and the optical path length is less affected and the structure is compact. According to actual use needs, each sub-mirror can also be sequentially arranged in different rotary lenses so as to realize more light spot form changes. However, in this case, if a uniformly distributed light spot is required, at least two sub-mirrors need to be rotated simultaneously.

In practical application, the number of the sub-mirrors in the positive/negative conical mirror can be designed according to the actual requirement on the output laser spot. However, in order to ensure that the flexible switching between the circular and arc-shaped light spots can be realized, the sum of the arc angles of the sectors corresponding to the projections of all the sub-mirrors in the positive conical mirror 132 and the negative conical mirror 131 in the propagation direction of the parallel light beams should be ensured to be 360 degrees. In order to obtain a plurality of arc-shaped section light spots which are uniformly distributed so as to ensure that the laser energy is uniformly distributed, the included angle between adjacent sub-mirrors in the positive/negative conical mirror can be set to be the same angle. In a preferred embodiment provided herein, the negative cone mirror 131 may also be comprised of a predetermined number of discrete sub-mirrors; and each sub-mirror has a sector with an arc of a predetermined angle. For example, the negative cone mirror 131 is composed of three separate sub-mirrors; each sub-mirror has a sector with an arc of 60 degrees; the three sub-mirrors are distributed in central symmetry. Thus, more different types of output light spots can be obtained, and more choices are provided for users.

Referring to fig. 15-16, in an embodiment of the present disclosure, a collimating lens 12, a complementary conical lens group 13, and a focusing lens 14 are sequentially disposed in a lens barrel 15. The lens barrel 15 includes: a collimating lens barrel 151; a focus lens barrel 152 coupled to the collimating lens barrel 151. The collimating lens 12 and the negative conical lens 131 in the complementary conical lens group 13 are sequentially mounted on the collimating lens cone 151; the positive conical mirror 132 and the focusing mirror 14 in the complementary conical mirror group 13 are mounted to the focusing column 152. Wherein, focus lens cone 152 is equipped with rotary mechanism 1521, includes: an inner swivel 15211, an outer swivel 15212 and a connector 15213. The positive cone mirror 132 is coupled to the inner swivel 15211. One end of the focusing lens barrel 152 close to the negative conical mirror 131 is provided with a guide hole for installing the rotating mechanism 1521. The length of the guide hole can be designed into any length according to the requirement of the rotating angle. In this embodiment, the length of the guiding hole is designed to be a quarter of the circumference of the focusing barrel 152, and the corresponding rotatable angle is 0 to 90 degrees, and the width of the guiding hole is matched with the connecting piece 15213.

Specifically, the inner swivel 15211 of the swivel mechanism 1521 is mounted inside the focus lens barrel 152, and the outer swivel 15212 is mounted outside the focus lens barrel 152. That is, one end of the focusing lens barrel 152 near the collimator lens 12 is inserted into a groove formed by the inner rotating ring 15211 and the outer rotating ring 15212 of the rotating mechanism 1521. The inner rotating ring 15211 and the outer rotating ring 15212 are provided with mounting holes on the surfaces. The mounting holes are distributed along the radial direction of the rotating mechanism 1521, are collinear with the guide holes provided in the focus lens barrel 152, and have the same aperture size. The connecting member 15213 passes through the guide hole of the focus lens barrel 152 and the inner swivel 15211 and the outer swivel 15212 of the swivel mechanism 1521, thereby fixing the inner swivel 15211 and the outer swivel 15212 to the focus lens barrel 152. In addition, the surface of the outer rotating ring 15212 is provided with marks of the rotation angles of the positive conical mirror 132 and the negative conical mirror 131, so that the rotation angle of the positive conical mirror 132 can be accurately adjusted.

According to the rotation angle mark arranged on the outer rotating ring, the rotating mechanism is rotated to drive the regular conical mirror 132 to rotate, so that the form of the output light spot is adjusted. When the rotation angle is 0 degrees, the positive conical mirror 132 and the negative conical mirror 131 are overlapped to output spot light; when the rotation angle is 90 degrees, the center of the output light spot is a point light spot, and the periphery of the output light spot is a complete circular light spot; when the included angle of the axis of the lens is between 0 degree and 90 degrees, the center of the output light spot is a point light spot, and the periphery of the output light spot is 4 symmetrical arc-shaped light spots.

The embodiment of the present application further provides a complementary conical lens group 13 for a laser processing system. Laser processing systems have been widely used in the fields of optoelectronics, material processing, and military. The laser processing system provided by the application is mainly applied to the field of material processing, for example, the fields of material cutting, circuit board processing, material welding and the like. Due to the high stability and high efficiency of the laser, it can easily perform precise processing on industrial materials. When the laser is focused on one point, the energy density of a focusing area is large, a heat affected zone is small, and the laser has the characteristics of small pollution, low material consumption, deep penetration, strong adaptability and the like in the processing process. However, since the directly output laser energy is concentrated, when the laser energy is applied to thin plate welding, undesirable phenomena such as splashing and perforation are easy to occur, and when the gap between the workpiece plates is large, the welding process is easy to be unstable, and the welding seam is not full. Although the energy distribution of the edge of the annular light spot is uniform, the problems of welding spatter, perforation and the like can be effectively solved. However, the laser processing system has a large divergence angle, and if a structure with a long optical path is used, the device has a large caliber, and is inconvenient to apply. The existing lens combination realizes the structure of annular light spots, such as the structure of a biconical lens or the structure of a catadioptric light path, and the light path is longer and is not suitable for a laser processing system.

It should be noted that in laser welding, the energy distribution is related to the area ratio of the transmitted beam. Therefore, the laser energy distributed by the annular light spot area is different from that distributed by the point light spot area. The energy distribution adjustment of the annular light spot region and the point light spot region can be realized by adjusting the areas of the point light spot region and the annular light spot region. The area of the annular light spot area can be adjusted by converting the annular light spot into a plurality of arc-shaped light spots. The area of the arc-shaped light spot is changed by adjusting the sum of the corresponding central angle angles of the arc-shaped light spot. The area of the arc-shaped light spot is increased, and the energy of the arc-shaped light spot area is increased. Correspondingly, the energy of the central spot area becomes lower. The areas of the point light spot area and the annular light spot area can be adjusted through corresponding lens combination. In other words, in the collimation focusing light path, a lens combination capable of adjusting the area ratio of the point light spot region to the annular light spot region is added to change the propagation direction of all or part of the laser beams, thereby realizing the purpose of changing the light spot form. The lens combination capable of adjusting the area ratio of the point light spot area to the annular light spot area is added on the basis of the original light path of the laser processing system, so that the processing requirements under different application scenes can be met. And the structure is compact, and the influence on the optical path length is small.

Therefore, the present application further provides a complementary conical lens group 13 capable of changing the propagation direction of the laser beam to adjust the areas of the spot area and the annular spot area. In one embodiment provided in the present application, the complementary conical mirror group 13 can be used for propagating parallel laser beams, that is, the beams incident on the complementary conical mirror group 13 are parallel laser beams, and the method includes:

a negative cone mirror 131;

a positive conical mirror 132 paired with the negative conical mirror 131 and coaxially rotatable with respect to the negative conical mirror 131;

wherein the negative cone mirror 131 comprises: a first core region 1311; a negative tapered mesa region 1312 adjacent to the first core region 1311;

The negative cone mirror 131 includes: a first core region 1311; a negative tapered mesa region 1312 adjacent to the first core region 1311. The first core region 1311 may be understood here as a region where the propagation direction of the parallel laser beam is not changed. That is, the parallel laser beams propagate through the first core region 1311 of the negative cone mirror 131 without changing the propagation direction. In practical applications, the first core region 1311 may be a region of the negative conical mirror 131 where the light beam incident surface is parallel to the light beam exit surface, or a virtual hollow-out region without any solid in the propagation direction of the laser beam. The negative tapered mesa region 1312 here may be understood as a region where a tapered surface is located higher than the light beam exit surface of the first core region 1311 in the light beam propagation direction. The angle between the tapered surface and the first core region 1311 may be designed according to practical circumstances. Here, the first core region 1311 may be understood as being in a spatially connected relationship with the negative tapered mesa region 1312.

It should be noted that the tapered surface of the negative taper plateau 1312 is not a continuous conical surface. That is, the arcs at the edges of the negatively tapered mesa 1312 correspond to a central angle other than 360. That is, the projection of the negatively tapered mesa region 1312 onto the parallel laser beam propagation direction is not circular, but fan-shaped.

Further, in a preferred embodiment provided herein, the negative conical mirror 131 further includes: an edge region 1313 adjacent to the negative tapered mesa region 1312. An edge region 1313 is provided here to facilitate the processing and protection of the negative cone 131. It can be understood as the area of the negative cone mirror 131 that is not coplanar with the negative cone mesa 1312. Since the exit surface of edge region 1313 is not coplanar with negative tapered mesa region 1312, that is, the included angle between the exit surface of edge region 1313 and the exit surface of negative tapered mesa region 1312 with respect to first core region 1311 is different from the included angle between the exit surface of negative tapered mesa region 1312 and first core region 1311, the propagation direction of the parallel laser beam on the exit surface of edge region 1313 is different from the propagation direction of the laser beam emitted from negative tapered mesa region 1312. If the included angle of the extended surface of the edge region 1313 with respect to the exit surface of the first core region 1311 is smaller than the included angle of the exit surface of the negative tapered mesa region 1312 with respect to the exit surface of the first core region 1311, that is, the inclination of the extended surface of the edge region 1313 with respect to the exit surface of the first core region 1311 is increased, the propagation of the laser beam exiting through the edge region 1313 is more diffused. If the included angle of the extending surface of the edge region 1313 with respect to the exit surface of the first core region 1311 is greater than the included angle of the exit surface of the negative cone-shaped mesa region 1312 with respect to the exit surface of the first core region 1311, that is, the inclination of the extending surface of the edge region 1313 with respect to the exit surface of the first core region 1311 is reduced, the propagation of the laser beam exiting through the edge region 1313 is more convergent. If the edge region 1313 is parallel to the first core region 1311, the propagation direction of the light beam is unchanged compared to the incident light.

In a preferred embodiment provided herein, the plane in which the edge region 1313 lies is perpendicular to the axis of the negative cone mirror 131, i.e. the edge region 1313 is parallel to the first core region 1311. The light beam exiting through the edge region 1313 has a constant propagation direction. Therefore, the negative conical mirror 131 is convenient to mount in the lens, the total edge breakage phenomenon in the machining process is prevented, and the machining yield of the negative conical mirror 131 is improved.

The positive cone mirror 132 includes: a second core region 1321 corresponding to the first core region 1311 for realizing a central light spot; a positive tapered mesa region 1322 adjacent to the second core region 1321 and corresponding to the negative tapered mesa region 1312. The second core region 1321 may be understood as a region adjacent to the first core region 1311 and having a size that does not change the propagation direction of the parallel laser beam. That is, the parallel laser beam propagating through the first core region 1311 propagates through the second core region 1321 of the positive tapered mirror 132, and the propagation direction remains unchanged. In one embodiment provided herein, the second core region 1321 overlaps the first core region 1311 in a projection parallel to the direction of propagation of the laser beam. In practical applications, the second core region 1321 may be an area adjacent to the first core region 1311 and having a size corresponding to that of the beam incident surface and the beam emergent surface, or a virtual hollow-out area without any solid in the direction parallel to the propagation direction of the laser beam. The size of the gap between the second core region 1321 and the first core region 1311 has a small influence on the entire optical path length, which can be ignored. Generally, a gap of less than 1mm is reserved to prevent scratching of the negative and positive

conical mirrors

131 and 132. Here, the positive tapered land 1322 is understood to be the area where the tapered surface complementary to the negative tapered land 1312 is located in the direction of beam propagation. It should be noted that the complementary refers to the spatial relationship that the positive tapered mesa regions 1322 and the negative tapered mesa regions 1312 exhibit when they overlap. Here, the abutment may be understood as the spatial connection of the second core region 1321 and the forward tapered platform region 1322. The angle between the tapered surface of the positive tapered mesa 1322 and the second core 1321 may be designed according to the angle between the negative tapered mesa 1312 and the first core 1311. The tapered surface of the forward tapered mesa region 1322 is not a continuous conical surface. That is, the arcs of the edges of the forward tapered lands 1322 correspond to central angles other than 360 °. That is, the projection of the forward tapered lands 1322 onto the parallel laser beam propagation direction is not circular, but fan-shaped. The tapered surface of the positive tapered land 1322 can be designed according to the tapered surface of the negative tapered land 1312, so that the positive tapered mirror 132 can rotate coaxially with respect to the negative tapered mirror 131.

In one embodiment provided herein, the incident plane of the negative conical mirror 131 is perpendicular to the direction of light beam propagation; the exit face of the positive conical mirror 132 is perpendicular to the direction of beam propagation. And, a space for facilitating the rotation of the lens is provided between the negative conical mirror 131 and the positive conical mirror 132.

Specifically, the incident surface of the negative conical mirror 131 is perpendicular to the beam propagation direction, that is, the projections of the first core region 1311, the negative conical mesa region 1312 and the edge region 1313 in the parallel laser beam propagation direction together constitute the incident surface of the negative conical mirror 131. At this time, since the exit surface of the laser beam propagating through the first core region 1311 is parallel to the incident surface, the propagation direction of the laser beam does not change. The laser beam propagating through the negative tapered mesa 1312 diverges because there is a certain angle between the exit surface and the entrance surface.

The exit face of the positive conical mirror 132 is perpendicular to the beam propagation direction, i.e., in the direction of propagation of the parallel laser beam, the exit face of the positive conical mirror 132 is parallel to the entrance face of the negative conical mirror 131. In other words, the projections of the second core region 1321 and the normal cone 1322 in the direction parallel to the propagation direction of the laser beam jointly constitute the incident surface of the normal cone mirror 132. The incident surfaces of the positive cone mirror 132 are a second core region 1321 corresponding to the first core region 1311, and a positive cone mesa region 1322 corresponding to the negative cone mesa region 1312. Since the second core region 1321 corresponds to the first core region 1311, the propagation direction of the parallel laser beam emitted from the first core region 1311 is unchanged by the propagation of the second core region 1321. The laser beam incident through the forward tapered mesa region 1322 can be condensed.

It should be noted that the projections of the negative tapered mesa regions 1312 and the positive tapered mesa regions 1322 in the direction parallel to the propagation direction of the laser beam are not circular, but fan-shaped. Moreover, since the negative conical mirror 131 and the positive conical mirror 132 can rotate, the included angle between the negative conical mirror 131 and the positive conical mirror 132 can be adjusted by rotating the same. In order to reduce the influence of the rotation gap between the positive tapered mirror 132 and the negative tapered mirror 131 on the propagation of the laser beam and ensure that the positive tapered mirror 132 and the negative tapered mirror 131 can rotate stably, in a preferred embodiment provided by the present application, the taper magnitudes of the negative tapered mesa region 1312 and the positive tapered mesa region 1322 are equal. Moreover, in order to ensure that the positive conical mirror 132 and the negative conical mirror 131 have the same propagation effect on the laser beam, in a preferred embodiment provided by the present application, the negative conical mirror 131 and the positive conical mirror 132 are made of a material having the same refractive index for light. The specific refractive index of the negative conical mirror 131 and the positive conical mirror 132 can be selected according to actual conditions.

When the negative conical mirror 131 and the positive conical mirror 132 coincide, the rotation angle therebetween is 0 °. At this time, the projections of the negative tapered land 1312 and the positive tapered land 1322 in the parallel laser beam propagation direction overlap. Since the incident surface of the negative conical mirror 131 is a plane perpendicular to the propagation direction of the light beam, and the exit surface of the positive conical mirror 132 is a plane perpendicular to the propagation direction of the light beam, the incident surface and the exit surface of the complementary conical mirror group 13 are parallel. And the distance between the two is small, which is equivalent to inserting a parallel flat plate in the light path. When the incident light is a parallel beam, the propagation direction is not changed. At this time, part of the parallel laser beams emitted from the collimator lens 12 is transmitted by the complementary conical lens group 13. Since the projections of the negative tapered mesa 1312 and the tapered mesa in the direction of the parallel laser beam propagation are fan-shaped, there is still a portion of the parallel laser beam that is not propagated by the complementary set of tapered mirrors 13. This portion of the laser beam does not change propagation direction. In summary, when the negative conical mirror 131 coincides with the positive conical mirror 132, the propagation direction of the parallel laser beam emitted from the collimating mirror 12 does not change.

The position where the negative conical mirror 131 and the positive conical mirror 132 are overlapped is taken as a starting point, any lens in the complementary conical mirror group 13 is rotated in any direction around the axis, and the included angle between the negative conical mirror 131 and the positive conical mirror 132 is changed. During the rotation, if there is still a partial overlap region between the negative conical mirror 131 and the positive conical mirror 132, the propagation direction of the parallel laser beam propagating through the overlap region is not changed. At this time, the negative cone mirror 131 and the positive cone mirror 132 have respective regions that are partially not overlapped, and the negative cone region 1312 and the projection of the cone region in the direction parallel to the propagation direction of the laser beam partially overlap. That is, the incident surface of the complementary set of conical mirrors 13 includes part of the positively conical mesa 1322 of the positively conical mirror 132 in addition to the incident surface of the negatively conical mirror 131; the exit surface of the set of complementary conical mirrors 13 comprises in addition to the exit surface of the positive conical mirror 132 also a part of the negative conical plateau 1312 of the negative conical mirror 131. At this time, the parallel laser beam existing portion is directly incident on the normal tapered land 1322 which is the overlapping portion, and the beams are converged. There is also a portion of the parallel laser beam exiting through the collimator lens 12 that exits directly from the negative tapered mesa 1312, which is the overlapping portion, and the beam diverges. It should be noted that there may still be portions of the incident parallel laser beam that do not propagate through the complementary set of conical mirrors 13. This portion of the laser beam does not change propagation direction. In summary, when the negative conical mirror 131 and the positive conical mirror 132 rotate to have a partial overlapping region, the parallel laser beams propagate through the complementary conical mirror group 13 to respectively obtain laser beams in converging, diverging and parallel states compared with the original parallel beams.

During rotation, if there is no overlapping area between the negative cone mirror 131 and the positive cone mirror 132, there is no overlapping area in the projections of the negative cone mesa region 1312 and the positive cone mesa region 1322 in the direction parallel to the propagation direction of the laser beam. At this time, the incident surface of the complementary set of conical mirrors 13 includes a positive conical land 1322 of the positive conical mirror 132 in addition to the incident surface of the negative conical mirror 131; the exit surface of the set of complementary conical mirrors 13 comprises, in addition to the exit surface of the positive conical mirror 132, a negative conical plateau 1312 of the negative conical mirror 131. At this time, the existing part of the parallel laser beam is directly incident on the forward tapered mesa region 1322, and the beam is converged. There is also a portion of the parallel laser beam that exits directly from the negative cone 1312, where the beam diverges. It should be noted that there may still be portions of the parallel laser beams that do not propagate through the complementary set of conical mirrors 13. This portion of the laser beam does not change propagation direction. Since the relative positions of the first core region 1311 and the second core region 1321 are not changed when the negative conical mirror 131 or the positive conical mirror 132 is rotated to adjust the included angle therebetween, the propagation direction of the laser beam propagating through the first core region 1311 and the second core region 1321 is not changed, and the laser beam is still a parallel beam. In summary, when the negative conical mirror 131 and the positive conical mirror 132 are rotated and there is no overlapping area, the parallel laser beams propagate through the complementary conical mirror group 13, and then converge, diverge and parallel laser beams are obtained respectively compared with the original parallel beams.

The parallel laser beams are transmitted by the complementary conical lens group 13 in any state and can be incident to the focusing mirror 14. It should be noted that the laser beam incident on the focusing mirror 14 may include parallel laser beams not propagating through the complementary conical mirror group 13, in addition to the laser beam emitted by the complementary conical mirror group 13. The focusing lens 14 is disposed in the laser propagation direction and coaxially distributed with the complementary conical lens group 13, and is adjacent to the exit surface of the complementary conical lens group 13. That is, the focusing mirror 14 and the complementary conical mirror group 13 are coaxially arranged, and the incident surface of the focusing mirror 14 is adjacent to the positive conical mirror 132 in the complementary conical mirror group 13. The focusing lens 14 is mainly used for focusing the laser beam emitted by the complementary conical lens group 13. In practice, the focusing lens 14 is typically a convex lens. When the light is transmitted by the convex lens, the light transmission direction passing through the optical center is unchanged; the light parallel to the main optical axis is refracted and passes through the focus of the light; the light rays passing through the focal point are refracted and then parallel to the main optical axis. If the incident beam of the focusing mirror 14 is a parallel beam, the beam is propagated by the focusing mirror 14, and a light spot with concentrated energy is finally obtained.

In one embodiment provided by the present application, when the negative conical mirror 131 coincides with the positive conical mirror 132, and the light beam emitted through the complementary conical mirror group 13 is incident on the focusing mirror 14, a light spot with concentrated energy is obtained. The size of the light spot is realized by adjusting the distance between the surface of the workpiece to be processed and the focusing mirror 14. The specific material and shape of the focusing lens 14 can be flexibly selected according to actual conditions.

It can be understood that when the negative conical mirror 131 and the positive conical mirror 132 are rotated, the laser beams are respectively converged, diverged and parallel compared with the parallel beam emitted from the collimating mirror 12. Wherein, the laser beam parallel to the parallel beam is transmitted through the focusing lens 14, and a spot can be obtained on the working surface. That is, when the negative conical mirror 131 partially overlaps the positive conical mirror 132, the light beam propagating through the overlapping portion of the complementary conical mirror group 13 propagates through the focusing mirror 14 to form the central spot. Alternatively, the central spot is formed by the part of the parallel laser beam that does not propagate through the complementary set of conical mirrors 13 propagating through the focusing mirror 14. Compared with the laser beam with the parallel beam in a divergent state, the laser beam is transmitted through the focusing mirror 14, and two symmetrical arc-shaped light spots can be obtained on the working surface. Compared with the laser beam in a convergent state of the parallel beam, the laser beam is transmitted through the focusing mirror 14, the beam is firstly converged at a focus, and when the beam is continuously transmitted, the beam is diverged. When the working surface is positioned behind the focal point, two symmetrical arc-shaped light spots with the same size as the focal point can be obtained on the working surface. It is noted that when the rotation angles of the negative conical mirror 131 and the positive conical mirror 132 are different, arc-shaped light spots with different sizes can be obtained. The length of the resulting arc-shaped spot is determined by the design values of the central angles of the negative tapered mesa 1312 and the positive tapered mesa 1322.

Specifically, when the overlapping portion of the negative conical mirror 131 and the positive conical mirror 132 is large, the resulting arc-shaped light spot area is small. At the moment, the areas of the arc-shaped light spot area and the point light spot area are smaller, the energy of the central light spot is high, and the energy of the arc-shaped light spot is low. When the overlapping portion of the negative conical mirror 131 and the positive conical mirror 132 is small, the resulting arc-shaped light spot area is large. The change of the area of the arc-shaped light spot is mainly reflected in the change of the arc-shaped length parameter of the arc-shaped light spot, and the width value of the arc-shaped light spot in the radial direction is not changed. At the moment, the area of the arc-shaped light spot area and the area of the point light spot area are larger, the energy of the central light spot is low, and the energy of the arc-shaped light spot is high. In addition, the outer diameter of the arc-shaped light spot is determined by the included angle between the negative cone-shaped platform region 1312 and the first core region 1311 and the included angle between the positive cone-shaped platform region 1322 and the second core region 1321. The larger the angle between the negative tapered mesa 1312 and the first core region 1311, the larger the angle between the positive tapered mesa 1322 and the second core region 1321, and the larger the angle at which the arc-shaped spot is offset. In this case, the outer diameter of the annular spot is larger under the condition that the focal length and the working distance are fixed. The angle between the negative tapered mesa region 1312 and the first core region 1311 and the angle between the positive tapered mesa region 1322 and the second core region 1321 may be designed according to the practical usage and requirements.

Experiments show that the energy distribution between the arc-shaped light spots and the point light spots is related to the area ratio of the transmitted light beams, and the energy and the angle change form a linear relation.

For example, when the negative conical mirror 131 partially overlaps the positive conical mirror 132, the light beam propagating through the overlapping portion of the complementary conical mirror group 13 propagates through the focusing mirror 14 to form a central light spot. If the total energy percentage of all the laser beams emitted from the focusing mirror 14 is 100%, and the beam passing through the part accounts for 50%, the edge-to-center energy ratio is theoretically 1: 1. The overlapping area of the projections of the negative conical mirror 131 and the positive conical mirror 132 in the direction of propagation of the parallel laser beam includes: the overlapping area of the first core region 1311 and the second core region 1321; the area of overlap of the projection of the negative tapered mesa regions 1312 and the positive tapered mesa regions 1322 in the direction of propagation of the parallel laser beam. Wherein the overlapping area of the projection of the negative tapered mesa region 1312 and the positive tapered mesa region 1322 in the direction parallel to the propagation direction of the laser beam is related to the angle corresponding to the overlapping fan. The area sizes of the first core region 1311 and the second core region 1321 may be designed according to the energy requirement of the central light spot, and may be designed to be circular. Also, the overlapping area of the first core region 1311 and the second core region 1321 does not change with the rotation angle of the negative conical mirror 131 and the positive conical mirror 132.

In a preferred embodiment provided by the present application, the sum of central angles corresponding to sectors obtained by projecting the negative frustum 1312 and the positive frustum 1322 in the direction parallel to the propagation direction of the laser beam is 360 °, that is, the sum of central angles corresponding to the arcs at the edges of the negative frustum 1312 and the positive frustum 1322 is 360 °. Thus, when the negative cone mirror 131 and the positive cone mirror 132 are rotated to a certain angle, the negative cone region 1312 and the positive cone region 1322 are projected as circles in the direction parallel to the propagation direction of the laser beam. At this time, a complete annular light spot on the surface of the workpiece can be obtained. With the rotation of the negative conical mirror 131 and the positive conical mirror 132, the projection of the negative conical land 1312 and the positive conical land 1322 on the propagation direction of the parallel laser beam changes, and the projections are distributed in a plurality of sectors. At the moment, a plurality of arc-shaped light spots can be obtained on the surface of the workpiece. Therefore, light spots in various different forms can be obtained on the surface of the workpiece, and flexible switching can be performed according to actual processing scenes.

Further, in a preferred embodiment provided herein, the negative conical mirror 131 comprises: two sectors with central symmetry; the radian of each sector is a preset angle. The two centrosymmetric sectors, i.e. the negative cone mirror 131, here comprise two centrosymmetric sectors projected in the propagation direction of the parallel laser beam. In one embodiment provided by the present application, each sector arc is 90 degrees, i.e. the central angle of the fan-shaped projection of the negative conical mirror 131 in the direction of propagation of the parallel laser beam is 90 °. At this time, correspondingly, the positive conical mirror 132 includes two sectors that are centrosymmetric, and each sector arc is 90 degrees.

When the positive conical mirror 132 and the negative conical mirror 131 are all overlapped, the propagation direction of the light beam propagating through the complementary conical mirror is unchanged. In this case, the projection of the complementary conical mirror group 13 in the direction of propagation of the parallel laser beam includes two centrosymmetric sectors, each sector having an arc of 90 degrees. Under the action of the focusing lens 14, the laser beam emitted by the complementary conical lens group 13 finally forms a spot on the surface of the workpiece.

When any one of the positive conical mirror 132 or the negative conical mirror 131 is rotated by 90 degrees and there is no overlapping area between the positive conical mirror 132 and the negative conical mirror 131, the projection of the complementary conical mirror group 13 in the propagation direction of the parallel laser beam is a circle, which includes four sectors, and the radian of each sector is 90 degrees. At this time, the positive tapered mirror 132 is completely separated from the rest of the negative tapered mirror 131 except that the first core region 1311 coincides with the second core region 1321. The incident surface of the complementary set of conical mirrors 13 is the incident surface of the negative conical mirror 131 and the positive conical mesa 1322 of the positive conical mirror 132. The laser beam incident through the incident surface of the negative cone mirror 131 is emitted from the negative cone 1312 and enters the focusing mirror 14. And finally two symmetrical quarter arc-shaped light spots are formed on the surface of the workpiece through the propagation of the focusing mirror 14. The laser beam incident through the forward tapered land 1322 of the forward tapered mirror 132 is emitted from the exit surface of the forward tapered mirror 132 and enters the focusing mirror 14. The light beam is firstly converged at the focus point by the propagation of the focusing mirror 14, and then is diverged when continuously propagating. When the working face is positioned behind the focal point, two symmetrical quarter circular arc-shaped light spots with the same size as the focal point can be formed on the surface of the workpiece. It is noted that the optical beam incident through the first core region 1311 exits through the second core region 1321 with a constant propagation direction. And finally forming a point light spot on the surface of the workpiece through the propagation of the focusing mirror 14. The four quarter arc-shaped light spots form a complete annular light spot, and the complete annular light spot and the central point light spot form a point annular light spot.

When either the positive conical mirror 132 or the negative conical mirror 131 is rotated by any angle between 0 deg. -90 deg., such as 60 deg., the positive conical mirror 132 partially overlaps the negative conical mirror 131. The projection of the complementary conical lens group 13 in the direction parallel to the propagation direction of the laser beam is fan-shaped. At this time, negative tapered mesa regions 1312 and positive tapered mesa regions 1322 have an overlapping region of an angle of 30 ° except that first core region 1311 and second core region 1321 coincide. The parallel laser beams propagate through the overlapping region (including the first core region 1311 and the second core region 1321), and the emergent rays are still parallel beams and enter the focusing mirror 14. This portion of the beam, propagating through the focusing mirror 14, eventually forms a spot on the workpiece surface. The parallel laser beams are transmitted through the non-overlapping area in the complementary conical lens group 13, and finally four discontinuous arc-shaped light spots are formed on the surface of the workpiece. The central angle corresponding to each arc-shaped light spot is 60 degrees, and is the same as the rotation angle of the positive/negative conical mirror. Arc-shaped light spots in different distribution states can be obtained by continuously adjusting the rotation angle of any one of the positive conical mirror 132 or the negative conical mirror 131, so that different requirements under different application scenes are met.

Further, in a preferred embodiment provided herein, the negative conical mirror 131 comprises: two separate sub-mirrors; each sub-mirror is provided with a sector with a radian being a preset angle; the two sub-mirrors are distributed in central symmetry. The separation here can be understood as the difference between the two sub-mirrors in the negative cone mirror 131 at a common connection. In one embodiment provided herein, the predetermined angle is 90 °. At this time, the projections of the two sub-mirrors in the propagation direction of the parallel laser beam are two sectors in a centrosymmetric and unconnected relation, and the radian of each sector is 90 degrees. Here, two separate sub-mirrors in the negative cone mirror 131 can be fixed to the same barrel to achieve a spatial relationship with their centers symmetrically distributed. The incident planes of the two sub-mirrors are coplanar and are positioned in the same plane perpendicular to the optical axis. Correspondingly, the positive conical mirror 132 comprises two sectors which are centrosymmetric, and the radian of each sector is 90 degrees; the two sub mirrors are distributed in a central symmetry way. Similarly, two separate sub-mirrors in the forward conical mirror 132 can be fixed to the same lens barrel to realize the spatial relationship of the central symmetrical distribution. Moreover, the incident planes of the two separate sub-mirrors in the forward conical mirror 132 are coplanar and are located in the same plane perpendicular to the optical axis. In this case, the first core region 1311 and the second core region 1321 may be understood as a virtual region without any solid matter in the direction parallel to the propagation direction of the laser beam, and are a circular hole, and the center line of the circular hole coincides with the beam axis.

When any one of the positive conical mirror 132 or the negative conical mirror 131 is rotated by 90 degrees and there is no overlapping region between the positive conical mirror 132 and the negative conical mirror 131, the projection of the complementary conical mirror group 13 in the direction parallel to the propagation direction of the laser beam is a circle, and the projection includes four sectors, and the radian of each sector is 90 degrees. At this time, the positive conical mirror 132 is completely separated from the negative conical mirror 131. The incident surface of the complementary set of conical mirrors 13 is the incident surface of the negative conical mirror 131 and the positive conical land 1322 of the positive conical mirror 132. The laser beam incident through the incident surface of the negative cone mirror 131 is emitted from the negative cone-shaped mesa region 1312 and enters the focusing mirror 14. And finally two symmetrical quarter arc-shaped light spots are formed on the surface of the workpiece through the propagation of the focusing mirror 14. The laser beam incident through the forward tapered land 1322 of the forward tapered mirror 132 is emitted from the exit surface of the forward tapered mirror 132 and enters the focusing mirror 14. After the propagation of the focusing mirror 14, the light beam is firstly converged at the focal point, and when the propagation is continued, the light beam is diverged. When the working surface is positioned behind the focal point, two symmetrical quarter circular arc-shaped light spots with the same size as the size can be formed on the surface of the workpiece. It is noted that the optical beam incident through the first core region 1311 exits through the second core region 1321 with a constant propagation direction. And finally forming a point light spot on the surface of the workpiece through the propagation of the focusing mirror 14. The four quarter arc-shaped light spots form a complete annular light spot, and the complete annular light spot and the central point light spot form a point annular light spot.

When either the positive conical mirror 132 or the negative conical mirror 131 is rotated by any angle between 0 deg. -90 deg., such as 60 deg., the positive conical mirror 132 partially overlaps the negative conical mirror 131. The projection of the complementary conical lens group 13 in the direction parallel to the propagation direction of the laser beam is fan-shaped. At this point, there is a 30 ° angle overlap region between the negative tapered land 1312 and the positive tapered land 1322. The parallel laser beams propagate through the overlapping region (including the first core region 1311 and the second core region 1321), and the emergent rays are still parallel beams and enter the focusing mirror 14. This portion of the beam eventually forms a spot on the workpiece surface as it propagates through the focusing mirror 14. The parallel laser beams are propagated through the non-overlapping area in the complementary conical lens group 13, and finally four discontinuous arc-shaped light spots are formed on the surface of the workpiece. The central angle corresponding to each arc-shaped light spot is 60 degrees, which is the same as the rotation angle of the positive/negative conical mirror. Arc-shaped light spots in different distribution states can be obtained by continuously adjusting the rotation angle of any one of the positive conical mirror 132 or the negative conical mirror 131, so that different requirements under different application scenes are met.

It should be noted that, by designing the positive conical mirror 132 and the negative conical mirror 131 as centrosymmetric, separate sub-mirrors, and each sub-mirror has a sector with an arc of 90 degrees, the switching between the circular light spot and the arc light spot can be realized with the minimum number of lenses, and the optical path length is less affected and the structure is compact. According to actual use needs, all the sub-mirrors can be sequentially arranged in different rotary lenses so as to realize more light spot form changes. However, in this case, if the light spots are required to be uniformly distributed, at least two sub-mirrors are required to be rotated simultaneously.

In practical application, the number of the secondary mirrors in the positive/negative conical mirror can be designed according to the actual requirement on the output laser spot. However, in order to ensure that the flexible switching between the circular and arc-shaped light spots can be realized, the sum of the arc angles of the sectors corresponding to the projections of all the sub-mirrors in the positive conical mirror 132 and the negative conical mirror 131 in the propagation direction of the parallel light beams should be ensured to be 360 degrees. In order to obtain a plurality of uniformly distributed arc-shaped section light spots and ensure uniform distribution of laser energy, the included angle between adjacent sub-mirrors in the positive/negative conical mirror can be set to be the same angle. In a preferred embodiment provided herein, the negative cone mirror 131 may also be comprised of a predetermined number of discrete sub-mirrors; and each sub-mirror has a sector with a radian at a preset angle. For example, the negative cone mirror 131 is composed of three separate sub-mirrors; each sub-mirror has a sector with an arc of 60 degrees; the three sub-mirrors are distributed in central symmetry. In this way, a greater variety of different types of output spots can be obtained, providing the user with a greater variety of options.

It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the statement that there is an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art to which the present application pertains. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A laser machining system, comprising:

a laser generating device generating a light source in an excited state;

the focusing mirror is arranged in the laser propagation direction, is coaxially distributed with the collimating mirror and is adjacent to the other side of the complementary conical mirror group opposite to the adjacent side of the collimating mirror;

wherein the complementary set of conical mirrors comprises:

a negative conical mirror;

the negative cone mirror includes:

a first core region;

a negatively tapered mesa region adjoining the first core region;

the positive conical mirror includes:

2. The laser machining system of claim 1, wherein the negative cone mirror further comprises:

an edge region adjacent to the negatively tapered mesa region.

3. The laser machining system of claim 1, wherein the negative tapered land and the positive tapered land have equal magnitudes of taper.

4. The laser machining system of claim 3, wherein the negative cone mirror comprises:

two sectors with central symmetry;

the radian of each sector is a preset angle.

5. The laser machining system of claim 3, wherein the negative cone mirror comprises:

two separate sub-mirrors;

each sub-mirror is provided with a sector with the radian being a preset angle;

the two sub-mirrors are distributed in central symmetry.

6. The laser machining system of claim 3, wherein the negative cone mirror is comprised of a preset number of discrete sub-mirrors;

each sub-mirror has a sector with a predetermined angle of arc.

7. A complementary set of conical mirrors for use in a laser machining system, comprising:

a negative cone mirror;

wherein the negative cone mirror comprises:

a first core region;

a negatively tapered mesa region adjoining the first core region;

the positive conical mirror includes:

8. The complementary set of conical mirrors according to claim 7, wherein said negative conical mirror further comprises:

an edge region adjacent to the negatively tapered mesa region.

9. The set of complementary conical sections of claim 7, wherein said negative conical sections and said positive conical sections have equal magnitude of taper.

10. The set of complementary conical mirrors according to claim 9, wherein said negative conical mirror comprises:

two sectors with central symmetry;

the radian of each sector is a preset angle.